## Elementary Geometry for College Students (6th Edition)

$x= 140^{\circ}$
Let the smaller angles be denoted by A and B since Sum of Angles of a Triangle = 180 Then in bigger triangle 2$\angle$A + 2 $\angle$B +100 =180 2($\angle$A +$\angle$B )=$80 THUS \angle$A +$\angle$B = 40 In Smaller triangle $\angle$A + $\angle$B +$\angle$X = 180 40 +$\angle$X = 180 $\angle$X = $140^{\circ}$